1. Field of the Invention
The present invention relates generally to valving devices for use in beverage dispensing systems, particularly those systems for drawing liquids, such as beer, from containers, such as beer kegs or barrels, using a gas to drive the liquid from the container. More particularly the present invention relates to an improved coupler for positive interconnection with a so-called "flat top" type of fluid container valve system for taping the valve system to draw liquid from the container.
2. Discussion of the Prior Art
In systems for tapping kegs of fluid and particularly containers of beer there has been used a valve assembly secured to the top of the keg for providing access to the fluid ultimately to be delivered from the keg to a remote position for distribution. Typically, the valve assembly includes a dual valve arrangement with a siphon tube which extends from the valve assembly to the bottom of the keg. The valve assembly is fixed within the keg neck or other valve receiving member to provide a valved access to the fluid once it is pressurized. The valve system, when tapped by a coupler or some other keg tapping means connected to a pressure source, allows pressurized gas to flow into the keg until the desired pressure within the keg is achieved to force the fluid out of the keg through the valve system and ultimately to a distribution device where the fluid can be used to fill glasses and the like. The valve system is one which allows the pressurized gas, usually carbon dioxide, to be forced out of the keg to distribution device until the keg is entirely emptied of fluid. Typically the valve system includes a recessed portion into which the coupler, or tapping mechanism, is closely received.
With regard to the coupler or other tapping mechanism, such mechanisms are typically inserted by rotation into the recessed portion of the valve assembly. Then by separate action, the handle is actuated to open the valves and permit the flow of fluid into and out of the keg in the appropriate channel. After the fluid has been completely dispensed from the keg, the reverse sequence is followed to reseal the valves. If the aforementioned sequence is followed, there will be no loss of fluid or gas in the tapping or untapping procedure.
One of the most effective systems ever devised to overcome the drawbacks of the prior art is described in U.S. Pat. Nos. 4,159,102 and 4,181,143. Broadly stated, the systems described in these patents provided better sealability between movable parts to prevent unnecessary leakage, safe operability to protect the operator even from his own errors, and constructional features facilitating cleaning operations and economic savings in manufacturing and assembly, among others. These systems use a coupler device which has a coupler body provided with a wedge surface which is helical in configuration circumscribing the bottom of the coupler body. The wedge surface is adapted to engage inwardly protruding lugs formed on the valve assembly. With this construction, upon rotation of the coupler into the valve system, the interaction of the wedge surfaces with the lugs forces the coupler body downwardly within the recessed portion of the valve assembly and into a sealing relationship with a flat surface provided proximate the bottom of the coupler receiving recess formed in the valve system.
The thrust of the present invention is directed toward providing an improved coupler assembly which can be used with a "flat top" valve system, that is, a valve system which does not have a coupler receiving recess. Flat top systems have several advantages including the absence of the coupler receiving recess which is difficult to clean and acts as a sump within which liquids and other foreign materials can accummulate. As will be apparent from the description which follows, the coupler assembly of the present invention is placed over the flat top surface of the valve system, rather than into a recess formed in the valve system and is positively secured to the outside surfaces of the keg neck or valve assembly receiving member. This permits both the valve system and the coupler to be more compact and avoids the necessity of forming the complex wedge surfaces on the coupled body. The problems inherent in forming the wedge surface engaging ears on the valve system and the propensity of these ears to possibly bend or break in operation is also uniquely avoided. Additionally, cleaning is simplified. The accummulation of foreign materials within the recess is avoided and superior sealing to atmosphere is achieved due to the unique design of the coupler to flat top sealing means of the invention.